Circuit breaker or interrupter



Oct. 16, 1956 T. J. GRECU 2,

CIRCUIT BREAKER OR INTERRUPTER Filed May 6, 1954' POW E R IN VEN TOR.

SOURCE LINE THOMAS J. GRECU 'POWERLINE ATT'YS g A- QJJVOLM United States Patent O CIRCUIT BREAKER R INTERRUPTER Thomas J. Green, Skokie, Ill. Application May 6, 1954, Serial No. 427,951 6 Claims. (Cl. 307-132) My invention relates to improvements in electrical circuit breakers or interrupters as used in electrical fence controllers.

It is the function of an electrical circuit breaker or interrupter as used in electrical fence controllers to provide a timed cyclic interrupted charge to the fence.

It is an important object of my invention to provide an electrical circuit breaker or interrupter, as used in electrical fence controllers, which controls the periodic delivery of an electrical impulse to the electric fence at a high current value, namely 18 milliamperes at 1800 volts alternating with a charge of low current value, viz., 3 milliamperes at 1100 volts, in a rhythmic cycle. In other words, the electrical fence remains charged at all times, although for approximately one-half of the time the charge is greatly reduced, thus affording an adequate safety factor while remaining effectively charged, and materially adding to the life of the transformer delivering the current charge to the fence.

Another object of my invention is that should the electrical fence become shorted my circuit breaker or interrupter automatically increases the time during which the fence remains charged at the higher current values mentioned above. This has the beneficial effect of preventing extraneous sources, such as growing weeds, from shorting the electrical fence and rendering it useless for its purpose.

Another important object of my invention is that should the heater element in the circuit breaker or interrupter fail for any reason, such as being burned out, the circuit breaker or interrupter permits current to flow to the electrical fence continuously at low current values, namely, viz., 3 mi'lliamperes at 1100 volts, thus keeping the electrical fence in effective operation until such time as the circuit breaker or interrupter can be replaced.

A further object of my invention is to provide an easy, effective method of varying the rate of interruption of the electric current being delivered to the fence. This is accomplished by mounting one of the electrical cont-act points on a set screw so that the distance between these points may be increased or decreased, thereby increasing or decreasing the time required for expansion and contraction of the bimetallic heater units.

Another feature of my invention is to make possible the use of high melting point metals in the construction of the electrical contact points, thus greatly increasing the life of said electrical contact points. This is accomplished by utilizing a condenser-resistor network across the contact points, thus providing for the penetration of oxide film which normally tends to form on such points during actual operation. The condenser-resistor network is of added value since it permits the use of very light contact point pressures ordinarily not practical under conventional electrical circuits.

In previous devices of this nature the heater element has been powered directly by a 110 volt alternating current source, while in my invention the element is powered through a high impedance inductance which de- Patented Oct. 16, 1956 creases the chance of the element being burned out by high potential electrical surges on the power line.

An illustrative embodiment of my invention is shown in the accompanying drawings, in which:

Figure 1 is a perspective View of the circuit breaker, or interrupter, made in accordance with my invention.

Figs. 2, 3 and 4 are side, end and bottom views of the device of Fig. 1.

Fig. 5 is a diagrammatic view.

Referring to the drawings, the components are sup ported by a fiber base 1 having three depending prongs 2, 3 and 4, adapted to fit into a corresponding plug-in socket in a fence controller unit. An offset bracket 5 is securely mounted on the face of the base 1 to which a bimetallic heater strip 6 is suspended. A contact 7 is mounted on the free end of the strip 6. As electric current flows through the resistance winding forming coil 8 on the strip 6, the wire becomes warm and the strip will bend towards the bracket '5. The heating of the strip 6 causes contact 7 to abut against contact 9 mounted on the end of set screw 10 which is mounted in bracket '5. This essentially breaks the current flowing through the coil 8. The current then essentially by-passes the coil '8 and flows through the bracket 5, through the bimetallic strip 6, which allows a high current flow of 18 milliamperes at 1800 volts to be discharged to the fence. Completing the cycle, as the bimetallic strip 6 cools it resumes its normal position, breaking the electric circuit across the contacts 7 and 9. As soon as this occurs and the electrical contact points 7 9 break apart the heater coil 8 is charged with the electric current and the bimetallic strip is again heated and the cycle resumes.

The set screw 10 is adjustable so that by increasing the gap between the points 7-9 the length of time during which the electrical charge is delivered to the electric fence may be predetermined by the user.

A resistor 11 is placed in parallel with the bimetallic strip 6 to cause a continuous flow of current of low amperage through the circuits between prongs -2 and 3. This has the effect that when the contact points 7-9 are open, the heater coil 8, wound about the bimetallic strip 6 is warming, the electric fence receives a continuous charge of low current value. When the electrical contact points '79 close the higher current value of 18 milliarnperes at 1800 volts is delivered to the fence. This 'has the added effect that should the heater coil 8 burn out, or for any reason become inoperative, a continuous flow of current, viz., 3 milliamperes at 1100 volts is discharged to the fence.

Fig. 5 illustrates the electrical wiring circuit of the above described unit as it is used in relation to the primary winding of the transformer 15 powering the fence charger 16. Also shown in Fig. 5, l have provided a choke coil 12 in the line between prong 3 and the bimet-al strip 6 and a condenser 13 and a small resistor 14 between prong 2 and the bimeta'l strip 6.

I prefer to employ a .1 mfd. 600 VDC (operating voltage-direct current) condenser 13 which has the function of charging during the off period of the interrupter, and releases a high voltage D. C. (direct current) discharge when contact points 7-3 are in engagement. This results in (a) high and low frequency waves are attenuated which results from the make and break of the contact points 7-9, reducing radio and television line conducted interference to accepted non-interference level as applied to electric fencing, and (b) the oxide of the tungsten contact poi-nts 7-9 is broken by the make and break high voltage discharge of condenser, resulting in a more stably timed interrupter.

I prefer to use a 10 ohm /2 watt resistor 14 which has is increased due to decreased peak hot condenser spark discharge, and b) the radiated high frequency radio interference waves are attenuated. It also performs the function as .a fuse if the condenser shorts out with the result that if the condenser shorts out and permits continuous 110 v. current passage, the resistor will burn out, terminating the hazard of :a continuous hi v. current feeding the fencer transformer as applied to electric fencing.

I prefer to use a 33 microhenries choke 12 which will perform the function of eliminating the line conducted electrical frequencies which will interfere with radio or television reception as applied to electric fencing, with the result that uncontrolled frequencies from the make and break of contact points 79, and uncontrolled frequencies from condenser discharge, are smothered and restricted, so as radio and television interferences are eliminated as applied to electric fencing. The choke 12 also serves the dual purpose of introducing a high impedance inductance into the circuit which materially decreases the probability of damage to the heater coil 8 from abnormal high potential electrical surges in the source of electrical energy connected to the fence charger.

Summarizing the foregoing, it can readily be understood from Figure that when the contacts 7 9are open there exists three parallel circuits permanently connected in series with the primary Winding of transformer 15, v-iz., (a) prong 3 through choke 12 serially connected to resistor 11 to prong 2, (b) prong 3 through choke 12 serially connected to heater coil 8 to prong 2, and (c) prong 3 through choke 12 serially connected to condenser 13 and resistor 14 to prong 2. When the contacts 7-9 are in closed position, the three parallel circuits (a), (b) and (c) are connected but essentially by-passed or shorted out electrically, whereupon the current essentially flows in a circuit comprising prong 3 through choke 1'2, bi-metal strip 6, contacts 7--9 to prong 2.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the construct-ion shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

lclaimz 1. A circuit-breaker mechanism comprising, three per manently closed parallel circuits mounted for interposition between a source of power and a piece of equipment, one of the circuits maintaining a low current value, means in another circuit for creating a higher current value, thermostatically controlled means in the third circuit for intermittently releasing the charge from the other circuit.

2. A circuit-breaker mechanism comprising, a base mounting, elements for interposition in a circuit from a source of power to a piece of equipment, three permanently closed parallel circuits connected to the elements, one of the circuits maintaining a low current value, means in another circuit for creating a higher current value, thermostatically controlled means in the third circuit for intermittently releasing the charge from theother circuit.

3. A circuit-breaker mechanism comprising, a base mounting, elements for interposition in a circuit from a sourceof power to a piece of equipment, three permanently closed parallel circuits connected to the elements, means in one of the circuits for maintaining a low current value, other means in another circuit for creating a high current value, a thermostat in the third circuit, and a contact also in the third circuit positioned for engagement by the thermostat for shorting the same and releasing the higher current value charge.

4. A circuit-breaker mechanism comprising, a base mounting, elements for interposition in a circuit from a source of power to a piece of equipment, three permanently closed parallel circuits connected to the elements,

one of 'the circuits maintaining a low current value to the equipment, means in another circuit for creating a high current value to the equipment, a bi-metal member having a juxtaposed heating coil both of which are connected in the third circuit, and a contact also in the third circuit positioned for engagement by the member to short the heating coil and release the charge from the other circuit to the equipment.

5. A circuit breaker or interrupter for an electrical circuit including an electric fence charger having a transformer, comprising an insulator base, a vertically disposed mounting bracket secured at one end to said base, the upper end of said bracket being offset, a bi-metallic element insulatively secured at one end to the upper end of said bracket and depending therefrom, said bi-metallic element being connected in circuit between one side of a source of electric power and the primary circuit of the transformer, a contact on the other end of said bimetallic element, a heater coil disposed around :said bimetallic element and-electrically secured at one end to said element adjacent said contact, an adjustable second contact on said bracket in cooperative alignment with said first-mentioned contact and connected in the circuit with the other end of said heater coil and the aforesaid side of said source of electric power, a large resistor in the circuit in parallel with said bi-metallic element, a small resistor and a condenser in the circuit between said himetallic .element and the adjustable contact and the aforesaid side of the said source of electric power, and a choke coil in the circuit between said bi-metallic element and the :said one side of the primary circuit of the transformer, the other side of the primary circuit of said transformer being connected to said other side of said source of electric power.

6. A cyclic electrical circuit interrupting device serially connectable between a piece of equipment, a source of electric power comprising, an insulator base having a pair of terminals, a vertically disposed mounting bracket secured at its :lower end to said base, an elongated bimetallic element insulatively secured at one end thereof to the upper end of said bracket and depending therefrom, said bi-metallic element adapted to deflect in response to temperaturevariation, a first contact disposed at the otherend of said bi-metallic'elemen-t, a second contact adjustably mounted on the lower portion of said bracket, said first contact adapted to abut said second contact when the temperature of said bimetallic element attainsa predetermined limit, a heater coil disposed about said bi-metallic element, one end of said heater element being electrically connected to said bimetallic element, the other end of said heater coil being electrically connected to said second contact, a choke coil mounted on said base adjacent said bracket, one end of said choke coil being electrically connected to said bi-meta'llic element and the other end connected to one of said terminals, and said second control being electrically connected to the other of said terminals whereby said heater coil and said choke coil are serial ly connected in circuit when said contacts are in open position thereby causing a temperature elevation ofsaid heater coil and bi-metallic element for deflection thereof to close said contacts whereupon said heater coil is bypassed from said circuit while said contacts are in a closed position.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,754,622 Gage Apr. 15, 1930 2,185,950 'Rose Ian. 2, 1940 2,190,282 Browner Feb. 13, 1940 2,220,687 Peters Nov. 5, 1940 V FOREIGN PATENTS 10,'96"5 Great Britain May 6, 19151 

